Abstract Recently Cu has been used as a replacement of Al in microelectronics industry to its lower electrical resistivity and higher electromigration resistance than aluminum. It is essential to have high performance diffusion barrier to suppress the diffusion between Cu and Si . In this experiment ZrN was investigated as a possible diffusion barrier. All coatings were deposited by RF magnetron reactive sputtering system. The growth of ZrN has been evaluted at different vacuum condition¡BRF power¡Bgrowth time¡BN2 flow rate Ar flow rate and Zr or ZrN target. The thin films were then annealed at temperatures from 450 ¢J to 700 ¢J for 30 min to study its durability. In this work XRD was used to study the thin film structure, SEM and TEM study the microstructures and AFM to study the surface roughness . The film¡¦s resistivity was measured as a function of N2 flow rate and annealing temperature by four point probe . For pure Zr film Cu3Si phase has formed after annealing at 550 ¢J for 30 min . As to ZrN film, only CuZr2 is present after annealing at 650 ¢J for 30 min indicating the diffusion barrier is still effective. After annealing at 700 ¢J for 30 min, Cu3Si was detected indicating the failure of the diffusion barrier. Results up to now suggest that ZrN layer can be a successful candidate as a diffusion barrier between Cu and Si.

With the given information that dendrimers have precisely controlled their sizes and spherical structures in the molecular level, the aim of this study is to show that dendrimer particles can become ordered into a self-assembled regular structure due to the nature of their regular sizes and shapes. For this project, melamine based generation 3 dendrimer was used for solution cast of thin films from the dendrimer-chloroform solutions with different casting conditions, i.e. various solution concentrations, casting temperatures, and substrates. As a result of these experiments, unique phenomena of highly ordered uniform 2-D contraction separations were observed during the solvent evaporation from the dendrimer films. The cast films from the concentration of 0.8 wt% and higher exhibit regular 2-D separation contraction patterns and make well-developed regularly arrayed structures due to the interaction between the contraction stresses and adhesion strength between films and substrates. From the DSC tests, both powder and cast film samples of a dendrimer show similar melting behaviors with different areas under the melting peaks. The results of these tests show that dendrimers, when they are in a descent environment that provides dendrimers with molecular mobility due to surface ionic bonding strength, can make a structural order and regularity in their macroscopic structures.

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Transparent Conductive Oxide thin films (TCO) with low resistivity and high light transmission act as transparent electrode for many kinds of display panel. At present, Indium Tin Oxide (ITO) is common transparent electrode material. Because Indium is classified rare element, and it has toxicity. Moreover ITO is unstable in high temperature. Recent years many researches are searching adaptive materials to replace ITO. Al doped ZnO (AZO) has same characteristics of low resistivity and high light transmission, it is one of the adaptive materials. In this study, we choice AZO and ITO target. Sputtering is a common method to deposition TCO. We sputtered the AZO film and ITO film on glass substrate and measured the characteristics respectively. In addition, because Liquid Phase Deposition (LPD) has advantages of simple process, low cost and large amount of wafers can be used. Therefore, in this study we growth ZnO thin film on glass substrate simultaneously, and doped Aluminum to increase conductivity.

Thesis (Ph. D.)--Lehigh University, 2003. / Includes vita. Includes bibliographical references (leaves 110-117).

In general, La-based high-k gate dielectric owns superior properties to offer transistor excellent characteristics. Thus, amorphous InGaZnO thin-film transistor with La-based high-k gate dielectric has been investigated in this thesis. Different approaches have been adopted to improve the device performance. First of all, the influence of gate-dielectric annealing in oxygen for different times on the device characteristics of the amorphous InGaZnO thin-film transistor with HfLaO gate dielectric has been investigated. It is demonstrated that this annealing treatment can effectively suppress the negative oxide charges. Moreover, it is discovered that this annealing treatment can suppress the acceptor-like border and interface traps. Accordingly, a high saturation carrier mobility of 35.2 〖cm〗^2/V∙s is achieved for the 30’-annealed device. Then, the effects of dielectric-annealing gas (O2, N2 and NH3) for a fixed annealing time of 10 min on the device characteristics are studied, and improvements by the dielectric annealing are observed for each gas. Among the samples, the N2-annealed sample has a high saturation carrier mobility of 35.1 〖cm〗^2/V∙s, the lowest subthreshold swing of 0.206 V/dec and a negligible hysteresis. On the contrary, the O2-annealed sample shows poorer performance due to a decrease of electron concentration in InGaZnO. Furthermore, the NH3-annealed sample displays the lowest threshold voltage (1.95 V) due to increased gate-oxide capacitance and generated positive oxide charges. Next, the effects of fluorine incorporation in amorphous InGaZnO by ion implant on the characteristics of InGaZnO thin-film transistor have been investigated. The electrical characteristics can be improved by this treatment due to increase of carrier concentration and passivation of defects in the InGaZnO film. Consequently, the saturation carrier mobility can be increased to 34.0 〖cm〗^2/V∙s, and the output current can be nearly doubled. However, device degradation is observed for very high fluorine dose above 1.0×1015 /〖cm〗^2. Then, another method for fluorine incorporation has been studied by treating the amorphous InGaZnO film in a CHF3/O2 plasma. The saturation carrier mobility can be improved to as high as 39.8 〖cm〗^2/V∙s. Then, a new high-k material is proposed by investigating the effects of Ta incorporation in the La2O3 gate dielectric of amorphous InGaZnO thin-film transistor. Since the Ta incorporation is found to effectively enhance the moisture resistance of the La2O3 film, both the dielectric roughness and trap density at/near the InGaZnO/dielectric interface can be reduced, resulting in a significant improvement in the electrical characteristics of the device. Nevertheless, excessive incorporation of Ta can degrade the device characteristics due to newly-generated Ta-related traps. Finally, the proposed TaLaO is compared with Ta2O5 as the gate dielectric of amorphous InGaZnO thin-film transistor. It is found that the electrical characteristics of the device can be effectively improved by the incorporation of La in the Ta2O5 gate dielectric, which is ascribed to the fact that La incorporation can enlarge the band gap of Ta oxide and its conduction-band offset with InGaZnO, and also reduce the trap densities in the Ta2O5 gate dielectric and at the InGaZnO/gate-dielectric interface. / published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

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Among the newly discovered iron-based superconductor, FeSe with the simplest structure and a transition temperature (T_c) around 8 K arouses much research interest. Although its Tc is much lower than that of the cuprates, iron chalcogenide has low anisotropy, slow decrease of the critical current density (J_c) with increasing magnetic field and high upper critical field H_c2 as well as easy composition control, which makes it a promising candidate to substitute NbSn/NbTi for high field applications. Compared with its bulk counterpart, iron-based superconductor thin film has a great potential in developing the ordered quasi-2D structure and is suitable for coating technology which has already been applied in YBa_2Cu_3O_7-x coated conductors. In this thesis, we first optimized pure FeSe thin films by different growth conditions using pulsed laser deposition (PLD) and post-annealing procedures. The microstructure properties of the films including the epitaxial quality, interface structure and secondary phase have been studied and correlated with the superconducting properties. Second, we reported our initial attempt on introducing the flux pinning centers into FeSe_0.5Te_0.5 thin films either under a controlled oxygen atmosphere or with a thin CeO_2 interlayer. The microstructure of the FeSe_0.5Te_0.5 films including the epitaxial quality, the interface structure and the secondary phase have been studied and correlated with the in-field performance of the superconducting thin films to explore the pinning properties of these nanoscale defects. Very recently, ion beam assisted deposition (IBAD) substrates have been used to grow high quality FeSe_0.5Te_0.5 tape with excellent in-field performance. The film on IBAD substrate involves multiple steps of seed layer and buffer layer deposition to establish the epitaxial growth template. Therefore a simplified and cost effective iron-based coated conductor is more desirable. Towards the practical application, we demonstrated the growth of superconducting FeSe_0.5Te_0.5 film on amorphous glass substrates for the first time. The film is highly textured with excellent superconducting properties, e.g., T_c of 10 K and J_c under self-field as high as 1.2×10^4 A/cm^2 at 4 K. Further optimization of the film growth with various nanoscale interlayers has been carried out. In addition the Te rich iron chalcogenide thin film with composition close to the composition with antiferromagnetic (AFM) transition has been demonstrated. Compared to the FeSe_0.5Te_0.5 which claimed to be the optimum composition from the literature report, the FeSe_0.1Te_0.9 is even more promising for the high field application with its coexistence of super high upper critical field and high critical current density.

No description available.

No description available.